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Comment by rkalla | Hacker News Reader

> "My colors look wrong" will not, and cannot, be--

Believe me, I would agree with you had I not been troubleshooting the issue for the last 4 years, but it did fix it.

It is entirely possible the guy ended up changing more than just the cable and didn't mention it.

This experience reminds me a lot of the Google Ops Team talk at Google I/O this year where they gave stats on things that caused outages and kept punctuating the point that things you think are impossible, will happen at-scale.

"HDMI is a digital signal, it either works or doesn't, degraded analog signal artifacts are impossible!"

Apparently not =/

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And this "it's digital" argument is bogus. The individual bit is either transmittes correctly or not, but the whole stream can have arbirary many bit errors which the receiver can only compensate up to a certain rate. There is usually good error correction on the audio streams (both listeners and speakers don't react well to sudden loud clicks), but errors in the video stream usually lead to artefacts that may be visible for are few fractions of a second or so (until the next full frame in the streams).

Whoever makes this "digital streams cannot degrade" argument has obviously never tried to watch DVB-T behind a hill.

DVB != HDMI.

I believe DVB-T uses MPEG-2 or some variation. While HDMI video doesn't use a motion vector based encoding. So when you have errors with MPEG-2, it could be on B or P frame which results in the delta from the previous I frame being drawn incorrectly (or not at all). With HDMI, the error won't show up in a delta frame (because there aren't any), rather just white pixels.

Never underestimate the power of the placebo effect.

I'd also like to say that digital signals should work or not work, however, when someones map doesn’t match the actual terrain, it’s usually not the terrain that’s wrong.

Could it be related to how the cable affects the transmitting or receiving circuitry? (Electrical impedance mismatch or crosstalk comes to mind.)

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